The Key Points of Dry Eye Disease or Keratoconjunctivitis Sicca

Today we'll be presenting the key points of one of the most common ocular diseases in dogs: Dry Eye Disease or Keratoconjunctivitis Sicca.

Keratoconjunctivitis Sicca is an ocular surface (cornea and conjunctiva) inflammatory disease secondary to at least one of the tear film phases deficiency that causes tear hyperosmolarity. This hyperosmolarity and increased friction will lead to secondary infections, dehydration and malnutrition of the cornea and conjunctiva and to an increased probability of corneal ulcerations. Chronic inflammation of the ocular surface will also end up generating conjunctival hyperaemia, hyperkeratinization and thickening of the corneal epithelium, corneal vascularization with increased migration of inflammatory cells and the corneal deposition of pigment, lipids, and calcium. The prognosis is usually favourable, although it will depend on the cause and whether an early effective and individualized treatment is implemented.

There are two major classifications of Keratoconjunctivitis Sicca:

  • Qualitative: Pathological decrease of the lipid or mucoid components of the tear film. In this case, the lacrimal gland is functional and the tear hyperosmolarity is due to an increase in its evaporation rate. The cause can be an acute/chronic damage or inflammation of the Meibomian glands and/or the conjunctiva goblet cells, such as in cases of infectious blepharitis, seborrheic dermatitis, etc.
  • Quantitative: Pathological decrease of the aqueous component of the tear film. In this case, hyperosmolarity is due to reduced secretion of the aqueous component under normal evaporation conditions. This is the most common initial presentation in dogs, although in most cases, a vicious circle is generated in which the other types of components of the tear film are also affected in the end.
Quantitative Keratoconjunctivitis Sicca causes are varied, such as infectious diseases, endocrine diseases, systemic immune-mediated/autoimmune diseases, iatrogenic (surgical), etc. although the most common is a localized and chronic immune-mediated inflammation of the lacrimal gland (immune-mediated adenitis). There are dog and cat breeds that are more predisposed, as we already mentioned in one of our previous posts in our social networks (Instagram, Linkedin), such as brachiocephalic breeds, West Highland White Terrier, Cocker Spaniel and American, etc.

The symptoms that may occur are: very characteristic mucous exudate, conjunctival hyperaemia, opaque cornea with neovascularization, oedema and corneal ulceration, etc.

To reach its diagnosis, we will have to look at the patient’s clinical history, to perform a general and ophthalmoscopic examination, if we suspect of systemic pathologies also some blood test and/or other complementary tests, and of course some specific ophthalmological tests: Shirmer Test, Fluorescein Stain, Lissamine Green Stain, TBUT (Tear Break-up Time), Impression Cytology and Osavet Test.

There are several types of systemic and topical medical treatments such as replacement tears (there is a great variety), topical immunosuppressants, etc. and in most of the cases, they will be prescribed at the same time. In addition, if there are secondary problems such as corneal infections or ulcers, they will also have to be treated. There are also surgical procedures such as transposition of the parathyroid duct, among others.

Another essential asset to help improve Keratoconjunctivitis Sicca symptoms, with proven efficacy in dogs, will be the supplementation with specific nutraceuticals such as Lacrimalis, rich in Omega-3 Fatty Acids that will improve tear quality, stability and its secretion, Lactoferrin with anti-inflammatory and antimicrobial properties on the ocular surface and antioxidants such as Vitamins E and C and the minerals Zinc and Copper.

Dr+Vet Pet Care by Böthmen Pharma, will be presenting each one of the different ophthalmological tests that we have mentioned in this article during the following weeks in association with Instituto Veterinario Oftalmológico (IVO) so you can learn more about them, stay tuned for more information!

The Key Points of Glaucoma

Last Saturday, March the 12th was World’s Glaucoma Day. Did you know that Glaucoma is one of the main causes of blindness in dogs? In order to increase the awareness and knowledge of this disease that is one of the most common ocular emergencies in the small animal practice, we’ll explain the key points of the pathology.

Glaucoma is a chronic neurodegenerative disease of the Optic Nerve and retina. It is characterized by an alteration in the balance between the production and the output of the aqueous humor, leading to its accumulation inside the eye and thus, an increase of the intraocular pressure (IOP). The consequences of the IOP increase are the progressive damage of the retinal Ganglion Cells leading to their apoptosis and the neuritis of the Optic Nerve that may lead to the loss of the patient's vision. The patient's prognosis is usually reserved, with most of them losing both eyes sight progressively and even in some cases, leaving the veterinarian with no other solution but the enucleation of the affected eye/s.

Glaucoma can be classified in the following different ways:

  • According to their evolution, we can classify them as acute or chronic.
  • Depending on the cause, we can differentiate them between:
    • Congenital
    • Primary: usually linked to hereditary factors. It is the most common in dogs.
    • Secondary to other intraocular pathologies. Most common in cats.
  • Depending on the morphology of the iridocorneal angle, they might be of:
    • Open angle: it is the most common in humans. There are some predisposed breeds, such as Beagle or Norweigan Elkhound.
    • Narrow angle
    • Closed angle: It is the most common kind in dogs. Some predisposed breeds are American and English Cocker Spaniel, Basset Hound, Chihuahua, Great Dane, Labrador Retriever, Chow-Chow, Shar-pei, etc. just as we already informed you some time ago in our social networks (Linkedin, Instagram).
In the most initial phases when the IOP is lightly elevated, the symptoms usually go unnoticed by the owners, but they will progress until the IOP is markedly elevated and in that moment the patient will present all or some of the following symptoms: severe pain, reddened eyes, photophobia (intolerance to light), epiphora (excessive and constant tearing), mydriasis (pupil dilation), etc.

To reach its diagnosis the veterinarians will have to look at the patient’s clinical history, perform a general and ophthalmological examination, measurement of IOP by tonometry (there is a variety of different ones in the market) and evaluate the morphology of the iridocorneal angle with gonioscopy. In some cases, other techniques such as high-resolution ultrasound may also be performed.

Various types of treatments, both medical (topical or systemic) and surgical (such as the different techniques of laser cyclodestructive surgery) can be used to try to reduce the IOP. Another key asset in the treatment of glaucoma to try to delay as much as possible the loss of the patient's vision, either in both eyes in early diagnosis or at least one of the two, when the vision has already been lost in one, will be the supplementation with nutraceuticals such as Glauco, rich in B group vitamins and other antioxidant and neuroprotective substances such as Ginkgo Biloba or wild blueberry, to help reduce the progression of the disease and then, protect the retina and the Optic Nerve from damaging free radicals due to increased oxidative stress and increase blood flow to the Optic Nerve.

In conclusion, the more information and knowledge we have about glaucoma and the earlier it is diagnosed, and the vision of both or at least one of the two eyes is preserved, the greater the opportunity for the treatment options to be more effective, reducing then the damage to the retina and Optic Nerve and improving the dog’s quality of life.